Patient monitor having context-based sensitivity adjustments

This application is a continuation of U.S. patent application Ser. No. 11/071,875, entitled “Application Identification Sensor,” filed Mar. 3, 2005, which will issue as U.S. Pat. No. 7,438,683 on Oct. 21, 2008, which, claims a priority benefit under 35 U.S.C. §119(e) from U.S. Provisional Patent Application No. 60/549,996, entitled “Application Identification Sensor,” filed Mar. 4, 2004. The present application incorporates the entirety of the aforementioned priority documents herein by reference.

Pulse oximetry is a widely accepted noninvasive procedure for measuring the oxygen saturation level of arterial blood, an indicator of a person's oxygen supply. A typical pulse oximetry system has a sensor, a monitor and a patient cable providing a communication path between the sensor and monitor. The sensor is adapted to attach to a tissue site, such as a patient's finger, and respond to hemaglobin constituents of pulsatile blood. The monitor is adapted to receive a physiological signal from the sensor and provide a numeric readout of the patient's oxygen saturation and pulse rate.

A conventional pulse oximetry monitor processes the physiological signal from the sensor based upon sensor calibration data, internal algorithm parameters and user-selectable operational parameters. The sensor may have an information element that is readable by the monitor and that identifies one or more characteristics of the sensor. These characteristics may relate to sensor components, such as emitter wavelength, or the sensor type, such as adult, pediatric or neo-natal. The monitor may select calibration data and internal parameters accordingly. An information element may be a passive device, such as a resistor, or an active device, such as a transistor network, a logic device or a memory chip. An information element is described in U.S. Pat. No. 5,758,644 entitled Manual and Automatic Probe Calibration, which is assigned to Masimo Corporation, Irvine, Calif. and incorporated by reference herein.

One aspect of an application identification sensor comprises a plurality of emitters configured to transmit light into a tissue site and a detector configured to receive the light after tissue absorption. The detector generates a signal responsive to the intensity of the light and communicates the signal to a monitor. An information element is readable by the monitor so as to identify a sensor application. The monitor presets at least one user-selectable operational parameter in response to the information element. In one embodiment, the application relates to emergency care and the user-selectable operational parameter is selected from the set of sensitivity and averaging time.

Another aspect of an application identification sensor is a method where a sensor is attached to a monitor and an information element is read. Data from the information element is associated with an application, and user-selectable parameters corresponding to the application are preset. In one embodiment, the application is identified as emergency related. In a particular embodiment, maximum sensitivity and minimum averaging time are selected for processing a signal from the sensor.

An aspect of an application identification apparatus comprises a sensor configured to generate a physiological signal and a monitor capable of processing the physiological signal so as to measure a physiological parameter responsive to a constituent of pulsatile blood. The monitor has an application identification input. User-selectable operational parameters for said monitor have values responsive to the application identification input. In one embodiment, the application identification input is provided by an information element associated with the sensor and readable by the monitor. In another embodiment, the application identification input is provided by a user-actuated button associated with the monitor.

FIG. 1 is a block diagram a pulse oximetry system utilizing an application identification sensor or an application identification user input or both.

FIG. 1 illustrates a pulse oximetry system 100 incorporating an application identification sensor 200 and a monitor 300 adapted to recognize the sensor 200 accordingly. The sensor 200 has emitters 210 adapted to transmit light into a tissue site and a detector 220 adapted to receive light after absorption by the tissue site and to generate a detector signal in response, as is well known in the art. The monitor 300 has drivers 310 that activate the emitters 210 and a front-end 320 that conditions and digitizes the detector signal for input into a digital signal processor (DSP) 330 , as is also well known in the art. The DSP 330 computes oxygen saturation and pulse rate and provides the results on a display. A user interface 340 allows a user to input selected operational parameters for the DSP 330 . A pulse oximeter monitor is described in U.S. Pat. No. 6,699,194 entitled Signal Processing Apparatus and Method and U.S. Pat. No. 6,650,917 entitled Signal Processing Apparatus, which are assigned to Masimo Corporation, Irvine, Calif. and incorporated by reference herein. A user interface is described in U.S. Pat. No. 6,658,276 entitled Pulse Oximeter User Interface, which is assigned to Masimo Corporation, Irvine, Calif. and incorporated by reference herein.

Also shown in FIG. 1 , the application identification sensor 200 also has an information element 230 , and the monitor has a corresponding information element reader 350 . Advantageously, the sensor 200 is manufactured with an information element 230 that identifies a particular application to the monitor 300 . The monitor 300 presets one or more user-selectable operational parameters accordingly. This reduces or eliminates the need for user input of operational parameters specific to a particular application. In an alternative embodiment, the monitor 300 has an application identification button, switch or other user-actuated device 342 that causes the monitor 300 to preset one or more user-selectable operational parameters.

In one particularly advantageous embodiment, the application identification sensor 200 is manufactured, packaged and/or labeled for use in a trauma or emergency care situation, and the information element 230 is configured to identify that application or use to the monitor 300 accordingly. For example, when such a sensor 200 is connected to the monitor 300 , the monitor 300 may select maximum sensitivity and minimum averaging time, providing hands-off optimum settings for these user-selectable operational parameters for a trauma care application. In an alternative embodiment, the monitor 300 has an application identification button 342 that is labeled for use in trauma or emergency care situations and that, when actuated, causes the monitor 300 to set user-selectable operational parameters accordingly.

For various applications, an application identification sensor 200 may indicate other user-selectable operational parameters relating to monitor alarms, displays, outputs and general characteristics to name a few. Alarm parameters may include alarm limits, delay and volume, for example. Display parameters may regard numeric, plethysmograph and trend formats to name a few. Output parameters may include, for instance, the analog output and alarm output types and digital output data formats. General characteristics may include operational modes such as maximum sensitivity and minimum averaging time cited above. General characteristics may also include averaging mode, such as described in U.S. Pat. No. 6,430,525 entitled Variable Mode Averager, which is assigned to Masimo Corporation, Irvine, Calif. and incorporated by reference herein. General characteristics may further include, for example, user key lock-out and password entry to enable user keys and other monitor functions.

An application identification sensor has been disclosed in detail in connection with various embodiments. These embodiments are disclosed by way of examples only and are not to limit the scope of the claims that follow. For example, although an application identification sensor has been described with respect to a pulse oximetry system, a sensor having an information element that identifies an application to a monitor can be utilized in systems capable of measuring physiological parameters other than or in addition to oxygen saturation and pulse rate. One of ordinary skill in art will appreciate many other variations and modifications.